Field of the Invention
The present invention relates to an engine system having a coolant control valve which may control a coolant flow through both an exhaust side and intake side of a cylinder block and a cylinder head for improving cooling efficiency and reducing fuel consumption.
Description of Related Art
An engine generates torque by burning fuel, and remaining energy is discharged as thermal energy. Particularly, the coolant absorbs the thermal energy as the coolant circulates through an engine, a heater, and a radiator, and discharges the heat outside of the engine.
If a coolant temperature of the engine is low, oil viscosity is high, frictional force and fuel consumption increases, and a temperature of exhaust gas rises slowly, extending a time period for catalyst activation, making a quality of the exhaust gas poor. Along with this, if the coolant temperature of the engine is low, a time period required for normalizing a function of the heater is extended, making occupants and a driver feel cold.
If the coolant temperature of the engine is excessive, knocking takes place, and if ignition timing is adjusted for suppressing the knocking, performance may become poor. If a lubricant temperature is excessive, lubrication may become poor.
Consequently, one coolant control valve has been applied for controlling a plurality of cooling elements with one valve, to maintain the coolant temperature high at a particular region, to maintain the coolant temperature low at other particular regions, and so on.
Of the plurality of cooling elements, the cylinder block and the cylinder head are important elements, and technologies for separately cooling the cylinder block and the cylinder head are being researched.
The cylinder block and the cylinder head have intake sides for drawing in comparatively low temperature outdoor air and exhaust sides for exhausting comparatively high temperature exhaust gas, and researches are ongoing for individually controlling temperatures of the exhaust sides and the intake sides to improve cooling efficiency and reduce fuel consumption.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.